Усилители мощности стерео — Primare A35.2

The A35.2 is a balanced-input stereo power amplifier from Primare of Limhamn, Sweden, and it is the highest-powered design Primare has made with its UFPD 2 analogue Class D technology. For this model Primare designed a new UFPD 2 output module and a new power supply rather than reusing the parts of its integrated amplifiers. It can run as a stereo amplifier or be bridged to mono, and Primare lists it at EUR 3,200 with a choice of titanium or black.

Key specs that matter

In stereo the A35.2 delivers 2 x 200 W into 8 ohm and 2 x 400 W into 4 ohm. Bridged, it gives 800 W into 8 ohm or 500 W into 4 ohm. There is one RCA and one XLR input pair, with 15 kohm and 30 kohm input impedance respectively. Full 200 W output into 8 ohm needs 2 V at the RCA input or 4 V at the XLR input, which corresponds to 26 dB and 20 dB of gain, and bridge mode adds 6 dB. Output impedance is below 0.02 ohm. Frequency response is 20 Hz to 20 kHz within 0.2 dB, THD plus noise stays under 0.008% at 10 W into 8 ohm over the full band, and the noise floor lies more than 110 dB down. The chassis is 430 mm wide and 145 mm high, 400 mm deep with connectors or 382 mm without, and weighs 11.7 kg.

Engineering and use context

The UFPD 2 error amplifier leaves the gain versus frequency curve untouched, so feedback stays active over the whole audio band with the help of a purpose-made coil inside the 2nd order output filter, and loop gain is kept constant across that range. Primare chose a switch mode supply with custom-wound transformers and extra capacitive storage for short peaks. It is rated at 900 W, against 600 W in the 150 W I35 integrated, which the company describes as 50% more supply power for the output modules. The Active Power-Factor Correction converter uses two PFC stages 180 degrees out of phase, working in transition mode to reduce ripple and interference with other mains equipment. The input stage sits on a four-layer circuit board to keep the signal path short. Idle consumption is below 28 W, with less than 0.4 W in standby.

Pairing

A preamplifier with XLR outputs can use the balanced input, and Primare intends the amplifier for demanding loudspeakers. A pair of A35.2 units in bridged mode gives each loudspeaker a dedicated amplifier when a system asks for more power. Two 12 V trigger sockets and an RS232 port tie it into a controlled system, and auto-sense wakes it from standby when a signal arrives. It drops back to standby after 20 minutes of silence unless the front standby switch, set inside the Primare logo, is held for five seconds to keep it on.

Alternatives

The Primare A34.2 is the earlier UFPD stereo power amplifier, rated at 550 W bridged.